Problem: Simplify the expression. $(-3k^{3}-3k)(-6k^{4}-k^{3}-4k^{2})$
Explanation: First use the distributive property. $ - 3 k^3 (-6 k^4) - 3 k^3 (- k^3) - 3 k^3 (-4 k^2) - 3 k (-6 k^4) - 3 k (- k^3) - 3 k (-4 k^2) $ Simplify. $ 18k^{7} + 3k^{6} + 12k^{5} + 18k^{5} + 3k^{4} + 12k^{3} $ $18k^{7}+3k^{6}+30k^{5}+3k^{4}+12k^{3}$ Identify like terms. $ { 18k^{7}} {+ 3k^{6}} {+ 12k^{5}} {+ 18k^{5}} {+ 3k^{4}} {+ 12k^{3}} $ Add the coefficients. $ { 18k^{7}} {+ 3k^{6}} {+ 30k^{5}} {+ 3k^{4}} {+ 12k^{3}} $